Many network security protocols depend on negotiating session keys between clients and servers using expensive asymmetric cryptography and then requiring servers to keep track of a large number of symmetric keys negotiated for each client session. End-to-end security means that there is data authenticity and/or confidentiality of data from one side of a communication in the network all the way to the other side, e.g., client-to-server and server-to-client. Traffic visibility means that servers and information technology (IT) monitoring devices can view the secured traffic. To some degree, these two goals oppose one another, but both are important for network security.
End-to-end security is important for both clients and servers in order to exclude third parties from tampering with traffic between the client and server, where the client is the most exposed to direct manipulation or tampering. Thus, the uniqueness of the client's secrets is paramount to prevent the compromise of one client from gaining access to the traffic of other clients. Traffic visibility is vital to the IT administration and requires the IT administration to observe traffic to detect abnormal phenomenon. Many current major security protocols only provide end-to-end security without concern for traffic visibility.
Recently, for efficiency, the industry has been moving towards single-key combined mode cipher for both packet encryption and authentication. The Advanced Encryption Standard (AES) specified by the US NIST is the de facto method for most network security protocols. For instance, AES-GCM (Galois-field and Counter Mode) is recommended to be the scheme for the IPsec protocol. US NIST and NSA provide guidance for the choice of key sizes. For the majority of applications today, a 128-bit key with AES128 operation is used. However, in the future, for applications of higher-level of security, a 256-bit key with AES256 operation might be required. With today's methods, the latency of key derivation for the 256-bit key with AES256 operation is much longer than it is for key derivation for the 128-bit key with AES128 operation. A traditional method of key derivation is a serial operation by iterative the one-way hash function, which is slower in hardware.